Vinylpyridine polymers are well known stabilizers and wicking inhibitors useful in the dye and ink jet-recording arts. Extensive research has been directed to processes for obtaining this polymer as easily isolatable microsized particles in a substantially pure state. Heretofore such processes comprise polymerizing the vinylpyridine monomer in aqueous alcohol solutions using water insoluble suspension agents namely a polyolefin or polyolefin carbonate suspension aids, as disclosed in U.S. Pat. Nos. 3,828,016; 3,947,526 and 4,824,910. However, these processes result in polyvinylpyridine (PVPYR) product intimately mixed with or embedded in the water insoluble suspension agent matrix. To recover the desired polyvinylpyridine it has been necessary to subject this product to a series of expensive and time consuming extractions with alcohol or other organic PVPYR solvents followed by solvent evaporation or other means of removal. The expense of producing the desired polymer in small particle size and in a high state of purity has limited its use in several potential applications as well as in the dye art.
It has also been found that poly(vinylpyridine) prepared by current methods is associated with non-uniformity in the black areas of images produced by ink jet recording. as discussed in the international PCT Patent WO 98/30392.
Accordingly, it is an object of this invention to provide a commercially feasible and economical process which overcomes the above disadvantages. Another object is to provide a process which produces the product in small bead-like particles from which PVPYR is directly recoverable in a substantially pure state. Still another object is to directly produce PVPYR in a stable condition suitable for storage, shipment. or direct use. These and other objects and advantages of this invention will become apparent from the following description and disclosure.